Lifting-jack.



No. 799,071. PATENTED MAY 9, 1905. H. s059099.

` LIFTING JACK. APPLIGATION FILED JULY 26. 1904.

llNiTED STATES Patented May 2, 1905.

HERMANN SCHROER, OF MANNHEIM, GERMANY.

LlFTlNG-JACK.

SPECIFICATION forming part of Letters PatentNo. 789,071, dated May 2, 1905. Application ined Juiy 26, 1904. serial No. 218,271.

T a/ZZ whom t may concern:

Be it known that l, HERMANN Soi-IROER, a citizen of the Empire of Germany, residing in Mannheim, in the Grand Duchy of Baden and Empire of Germany, have invented certain new and useful Improvements in Lifting- Jacks, of which the following is a specification.

This invention relates to certain improvements in the lifting-jack for which l received Letters Patent of the United States No. 761,418, dated May 3, 1904, said improvements being designed with the view of increasing the lifting stroke of the same, which is of special advantage for lifting railwaycars, moving-vans, and other heavy vehicles and which has also the advantage that the jack, owing to its increased lift, can be advantageously used as a tension or drawing mechanism; and for this purpose the invention consists of a lifting-jack which comprises a cylindrical casing, two telescoping spindles in said casing, a ratchet-wheel and pawl mechanism at the upper end of the casing, interiorly-threaded sleeves at the upper and lower ends of the cylindrical casing for engaging both screw-spindles,- and lifting mechanism connected with the head of the inner screw-spindle.

rFhe invention consists, further, of certain details of construction by which a draw action can be exerted by the jack, aswill be fully described hereinafter, and finally pointed out in the claims.

ln the accompanying drawings, Figure 1 represents a side elevation of my improved lifting-jack. Fig. 2 is a front elevation of the same. Fig. 3 is a vertical central section on line 3 3, Fig. 2. Figs. 4 and 5 are horizontal sections of two different pawl-andratchet mechanisms for the lifting jack. Fig. 6 is a side view of a stationary footiece, and Fig. 7 is a side-view of a movable foot-piece at the lower end of the jack.

Similar letters of reference indicate correspending parts.

Referring to the drawings, a is a cylindrical casing which is open at both ends and provided at its upper and lower ends with interiorly threaded stationary sleeves a a2,

which serve for guiding two telescoping'spindles b and c, of which the interior spindle b is adjustable within the exterior spindle c, as shown clearly in Fig. 3. The exteriorly-recessed sleeve a/ at the upper end of the casing a is recessed for guiding a circular ratchet-strap d, which incloses a ratchetwheel e, that is keyed to the recessed sleeve a. rThe ratchet-strap d is provided with a socket d, having a rectangular recess adj acent to the strap and a round socket d2 in line therewith for receiving a hand-lever g. ln the socket d is guided a spring-actuated pawl j', which projects into the spaces between the teeth of the ratchet-wheel e, the end of the pawl being provided at one side with a rectangular recess which engages the side of the next adjacent ratchet tooth, while the opposite side of the pawlfis rounded off, so that during the return motion of the lever g the pawl clears the teeth of the ratchet-wheel, while it is instantly returned into engagement with the same by the tension of the helical spring interposed between the head of the pawl and an interior shoulder of the socket d2. On the stem of the springpawlis arranged a milled head f, which is provided with a cross-pinj', that engages a transverse recess in the end of the socket d. When the milled head f is pulled outwardly against the tension of the spring, turned on its axis, and then released, the cross-pinfZ engages the transverse recess and holds the pawl' in a position for turning the ratchetwhee e in one or the opposite direction, so as to produce the extension or withdrawing of the telescoping spindles b and c.

To the upper end of the spindle b is attached a bracket t, which supports a rod t, that extends in downward direction alongside of the casing and carries at its lower end, near the lower end of the casing,`a liftinghook 2, which is intended to engage objects of smallerv height near the base of the jack. On the exterior of the casing is arranged a guide-strap k, which is attached to the hook i2 for the better support and guiding of the same. The supporting-rod t is connected by a screw is with the bracket fL, so that on removing the screw it can be readily removed with the lifting-hook i2. The screw-spindle Z) is provided at its upper end and the screwspindle c at its lower end with a draft-ring Zt and h, respectively, which are connected with the ends by pivot-bolts m m, the upper bolt m being made round and provided at one end with an eye Z, while the lower pivot fm is made slightly conical and also provided with an eye Z, said eyes serving for supporting the hand-lever g when the same is not required for use, as shown in Fig. 2. The lower conical bolt m serves for firmly clamping the movable foot-piece p. The eye Z of the upper pivot-bolt m is provided with an interior screw-thread, which engages a corresponding thread on the lever g, so that the same can be screwed home in the eye Z while being held by the lower eye without being liable of getting detached from the jack when not in use. The links at the head of the spindle Z) and on the lower end of the spindle c are intended also to be used as tension or draft links, the head being made of one piece, as it is not necessary to remove the same from the spindle. The lifting-hook can be removed from the ack when the draft-links are to be used. Either the head of the lifting-spindle Z) or the lifting-hook i2 can be used for lifting purposes, while the draft-links serve for tension .or draft purposes. The inner spindle Z) is provided with a right-hand screw-thread and the outer spindle c with a left-hand screw-thread, which permits the simultaneous extension or telescoping of both spindles. By means of the lever-actuated pawl-andratchet mechanism a double lifting or, draw action of the ack is obtained.

In place of the spring-actuated pawl f (shown in Fig. 4) the centrally-pivoted double pawl]p may be used, as shown in Fig. 5. In this case the pawlj'X is shifted from one side to the other of its center pin into engagement with the teeth of the ratchet-wheel e and then held in position therewith by the stop-piece fo, which is turned on its axis through an angle of one hundred and eighty degrees in the same manner as the springpawlf in Fig. 4, so that the double pawlj'X accomplishes practically the same function as the spring-pawlf.

In order to prevent the screwing of the eX- terior spindle c out of the casing, so that the parts become detached from each other, a stop-pin n is arranged with the upper part of the casing al below the ratchet-strap d, which stop-pin forms contact with the guide-strap k of the lifting-hook Z2 and arrests the further turning motion of the casing and the detaching of the same from the spindle c.

I-Iaving thus described my invention, I claim as new and desire to secure by Letters Patent- 1. A lifting jack, consisting of a cylindrical casing, two eXteriorly-threaded spindles located within the casing and telescoping one within the other, stationary interiorly-threaded sleeves at the upper and lower ends of the casing adapted to engage the screw-spindles, a pawl-and-ratchet mechanism on the upper sleeve for simultaneously actuating the spindles, a head at the upper end of the inner spindle provided with a bracket, and a lifting-hook guided on the cylindrical casing and connected by a supportpig-rod with the bracket, substantially as set orth.

2. In a lifting-j ack, the combination, with a cylindrical casing, of two tubular screwspindles telescoping one within the other within the casing, stationary interiorlythreaded sleeves at the upper and lower ends of the casing adapted to engage the inner and outer screw-spindles, the upper end of the inner screw-spindle being provided with a head, a pawl-and-ratchet mechanism on the upper sleeve, and draft-links pivoted to the liftinghead of one spindle and to the lower end of the other spindle to permit the use of the lifting-j ack for tension or drawing purposes, substantially as set forth'.

3. In a lifting-jack, the combination, with a cylindrical casing provided with stationary interiorly-threaded sleeves at its upper and lower ends, of telescoping screw-spindles engaged bysaid sleeves,and a pawl-and-ratchet mechanism on the upper sleeve of the casing and consisting of a ratchet-strap movable about said sleeve, a ratchet-wheel keyed to said sleeve and rotatable in said ratchet-strap, a spring-actuated pawl guided in a socket of the ratchet-strap, and means for reversing said pawl and locking it in one or the other position so as to move the ratchet-wheel in either direction, and a lever adapted to engage the hub of the ratchet-wheel, substantially as set forth.

4. In a lifting-jack, the combination of a cylindrical casing having stationary screwsleeves at its upper and lower ends, telescoping spindles having screw-threads of opposite direction engaged by said sleeves, a pawl-andratchet mechanism on the upper sleeve, a

head attached to the upperend of the inner spindle', an enlarged portion at the lower end of the outer spindle, bolts connecting the head and engaged respectively with the upper end of one and the lower end of the other spindles, said bolts being provided with eyes, and a hand-lever adapted to be connected with the pawl-and-ratchet mechanism for operating the same or to be supported in the eyes of the bolts when not required for use, substantially as set forth.

In testimony that I claim the foregoing as my invention I have signed my name in presence of two subscribing witnesses.

HERMANN SCHROER.

Witnesses:

HEINRICH KRUG FUGnUsooR, JOSEPH Il. SEUTF.. 

